Communication: Noble metal nanoparticles have been used for more than 2000 years. Applications currently under discussion include solar cell technology, catalysis, and nonlinear optics, where the enormous interfacial surface area of the colloidally dispersed metals and their unique electronic properties resulting from size quantization are exploited. The problem of the stability of these materials has been addressed by using amphiphilic copolymer micelles (see figure) as a nanostructured stabilization environment for the metal particles.